Plasma Abatement Device Chamber Temperature Control
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Solution Overview
Problem
Plasma abatement devices used in semiconductor processes face corrosion issues due to the reaction of hydrogen halides like HBr and HCl with stainless steel components, which reduces their efficiency and lifespan, especially when exposed to water vapor.
Innovation Solution
Maintaining the plasma abatement device's gas chamber at a temperature range of 120°C to 180°C inhibits the adsorption of water on stainless steel surfaces, preventing the corrosive reaction of hydrogen halides with metal constituents, thereby extending the lifespan of stainless steel components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plasma abatement device operates at normal temperature, then it can effectively treat gas streams, but stainless steel components corrode due to reaction with hydrogen halides and water vapor
Solution Approach 1:
The patent applies parameter changes by heating the gas chamber to a specific temperature range (120°C to 180°C) to alter the physical state of water vapor, converting it from an adsorbed state that causes corrosion to a vapor state that prevents corrosion while maintaining treatment effectiveness
Solution Approach 2:
The patent converts the harmful effect of water vapor (which causes corrosion when adsorbed) into a beneficial effect by heating it to prevent adsorption, thereby transforming the corrosive environment into a protective one that extends component lifespan
2Quantity of substance
If water vapor is present in the gas stream, then it provides oxygen and hydrogen for chemical reactions, but it adsorbs on stainless steel surfaces and causes corrosion
Solution Approach 1:
The patent changes the temperature parameter of the gas chamber to prevent water vapor adsorption, allowing water vapor to remain in the gas phase where it provides reactive species without causing corrosion
Solution Approach 2:
The patent applies preliminary action by heating the gas chamber before introducing the gas stream, ensuring that water vapor does not adsorb on stainless steel surfaces from the outset, thereby preventing corrosion before it can occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This temperature control method significantly increases the lifespan of stainless steel components and maintains the efficiency of the abatement device by preventing corrosion and ensuring effective gas treatment.
Implementation Method 1
heating the chamber to a temperature that inhibits adsorption of water on a stainless steel surface within the chamber
Implementation Method 2
a microwave plasma is initiated and sustained between the two electrodes from the gas flowing between the electrodes
Implementation Method 3
species within the gas stream are subjected to impact with energetic electrons causing dissociation into reactive species
Implementation Method 4
a waveguide conveys microwave radiation from a microwave generator into a gas chamber
Data Source
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AI summary
A method is described for treating gas exhaust from a polysilicon etch process, which uses a plasma abatement device to treat the gas. The device comprises a stainless steel gas chamber having a gas inlet for receiving the gas and a gas outlet. As the gas may contain a halocompound and water vapour, the chamber is heated to a temperature that inhibits adsorption of water on the surface within the chamber, thereby inhibiting corrosion of the gas chamber. The gas is then conveyed to the gas chamber for treatment, and the temperature of the chamber is maintained above said temperature during treatment of the gas.